CLE Anatomy & Physiology of Lactation 3 — Questions and Answers
Question 1: Lactogenesis II is defined as the onset of copious milk secretion. When does it typically occur?
- During the third trimester of pregnancy
- Within 30 minutes after delivery
- Between 30 and 72 hours postpartum (Correct answer)
- At 2 weeks postpartum
Correct answer: Between 30 and 72 hours postpartum
Lactogenesis II, triggered by the drop in progesterone after placental delivery and sustained prolactin, typically results in milk 'coming in' between 30–72 hours postpartum.
Question 2: Which stage of lactation describes the secretory differentiation of mammary epithelial cells that begins mid-pregnancy?
- Lactogenesis I (Correct answer)
- Lactogenesis II
- Lactogenesis III
- Mammogenesis
Correct answer: Lactogenesis I
Lactogenesis I (secretory differentiation) occurs around mid-pregnancy when alveolar cells differentiate into secretory lactocytes capable of producing small amounts of colostrum.
Question 3: What distinguishes colostrum from mature breast milk in terms of protein content?
- Colostrum has less protein than mature milk
- Colostrum and mature milk have equal protein levels
- Colostrum has higher protein concentration than mature milk (Correct answer)
- Colostrum contains no immunoglobulins
Correct answer: Colostrum has higher protein concentration than mature milk
Colostrum is concentrated with protein (especially secretory IgA, lactoferrin, and growth factors) at roughly 2–3 times the protein concentration of mature milk.
Question 4: Galactopoiesis refers to which phase of lactation?
- Initial development of breast tissue
- Onset of copious milk after birth
- Ongoing maintenance of established milk supply (Correct answer)
- Gradual cessation of lactation
Correct answer: Ongoing maintenance of established milk supply
Galactopoiesis (also called Lactogenesis III) describes the autocrine-driven maintenance of milk supply that depends on frequent and effective milk removal.
Question 5: The Feedback Inhibitor of Lactation (FIL) regulates milk supply through which mechanism?
- It stimulates prolactin release centrally
- It is a whey protein in accumulated milk that suppresses further secretion locally (Correct answer)
- It triggers oxytocin from the posterior pituitary
- It increases alveolar cell proliferation
Correct answer: It is a whey protein in accumulated milk that suppresses further secretion locally
FIL is a whey protein produced in the alveoli that accumulates when milk is not removed, signaling lactocytes to slow production via autocrine control.
Question 6: What is the primary carbohydrate in human breast milk and what function does it serve?
- Sucrose; provides energy only
- Fructose; promotes gut acidity
- Lactose; provides energy and promotes beneficial gut bacteria (Correct answer)
- Glucose; stimulates insulin secretion
Correct answer: Lactose; provides energy and promotes beneficial gut bacteria
Lactose is the predominant carbohydrate in human milk; it provides energy and is partially converted to galactose, which supports brain development and promotes Lactobacillus growth.
Question 7: Which component of breast milk is highest in hindmilk compared to foremilk?
- Lactose
- Secretory IgA
- Fat (Correct answer)
- Water
Correct answer: Fat
Fat content increases progressively within a feeding as milk is ejected from the alveoli, making hindmilk fat-rich compared to the more watery, lactose-rich foremilk.
CLE Anatomy & Physiology of Lactation 3
Lactogenesis II is defined as the onset of copious milk secretion.
When does it typically occur?